1. Field of the Invention
This invention relates to blocked jaw clutch assemblies and in particular to improved blocked jaw clutch assemblies for use in compound change gear transmissions wherein the main section utilizes manually engaged nonsynchronized, unblocked jaw clutches to selectively engage a selected main section ratio gear and wherein the auxiliary section utilizes blocked resiliently shifted jaw clutches to selectively engage a selected auxiliary ratio. Preferably, the blockers and associated clutch members in the auxiliary section have complementary ramps on the blocking members thereof configured to prevent nonsynchronized engagement of the associated jaw clutch members when the main section is engaged but which will tend to act as positioners to place the blocker and clutch member in a nonblocking condition when the main section is in a neutral or disengaged condition.
2. Description of the Prior Art
Compound transmissions of the splitter or range type, or a combination thereof, are well known in the prior art as may be seen by reference to U.S. Pat. Nos. 3,105,395; 3,648,546; 3,799,002; 2,932,988 and 3,229,551, the disclosures of which are all hereby incorporated by reference.
Blocked change gear transmissions of both the single and the compound types are also well known in the prior art as may be seen by reference to U.S. Pat. Nos. 3,799,002; 3,921,469; 3,924,484; 3,983,979; 4,132,122; 4,192,196 and 4,194,410, the disclosures of which are all hereby incorporated by reference.
Semi-blocked compound change gear transmissions wherein the main section utilizes manually engaged nonsynchronized, unblocked jaw clutches to selectively engage a selected main section ratio gear and wherein the auxiliary section utilizes blocked resiliently shifted jaw clutches to selectively engage a selected auxiliary ratio, and wherein the blockers and associated clutch members in the auxiliary section have complementary ramps, also called "sensor unblocker ramps", on the blocking members thereof configured to prevent nonsynchronized engagement of the associated jaw clutch members when the main section is engaged but which will tend to act as positioners to place the blocker and clutch member in a nonblocking condition when the main section is in a neutral or disengaged condition are known in the prior art as may be seen by reference to U.S. Pat. No. 4,440,037 and European Publication No. 0 071 353, published Feb. 9, 1983, of allowed European Patent Application No. 82 303 585.2 (corresponding to applicant's assignee's U.S. patent application Ser. No. 287,470, filed July 27, 1981), the disclosures of which are hereby incorporated by reference.
Automated and/or semi-automated blocked or semi-blocked change gear transmissions are known in the prior art as may be seen by reference to U.S. Pat. No. 4,527,447, the disclosure of which is hereby incorporated by reference.
The prior art semi-blocked compound transmissions, especially the splitter type, wherein the main transmission section is provided with well known nonsynchronized, unblocked jaw clutch assemblies, and the auxiliary transmission section is provided with resiliently shiftable blocked jaw clutch assemblies and, preferably, the blocked jaw clutch assemblies are provided with complimentary ramp members on the associated blocker and clutch members which will cause the blockers to prevent nonsynchronous engagement of the associated jaw clutch assemblies when the main transmission section is engaged but will allow the blocker to tend to rotationally move to a nonblocking position under the influence of a spring bias, when the main transmission section is in neutral, provides a relatively uncomplicated and reliable compound transmission which is shiftable with substantially the ease of a simple transmission and allows shifts to be completed with the vehicle in a static condition.
However, such transmissions, and the blocked jaw clutch assemblies utilized therewith, have been less than totally satisfactory in certain situations requiring increased unblocking force and/or an accurate signal, such as for automation purposes, of gear engagement derived solely from actuator position as the amount of axial force urging the complimentary ramped surfaces of the blockers into contact is limited to spring force and/or monitoring of the actuator piston position did not provide an accurate indication of gear engagement. Both drawbacks result from the structure and operation of the prior art blocked clutch assemblies wherein the actuator piston is moved to its fully displaced actuated position when moving the clutch members and biasing spring to the pre-select position.